[Mac] Prevent omnibox text bg from drawing over decoration, focus ring.

chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.h"
 
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"  // IDC_*
@@ skipping 580 matching lines @@
     return;
   NSAttributedString* selection =
       [self attributedSubstringForProposedRange:selectedRange
                                     actualRange:NULL];
   if (!selection)
     return;
 
   [[FindPasteboard sharedInstance] setFindText:[selection string]];
 }
 
+- (BOOL)isOpaque {
+  // Even if you call -setDrawsBackground:NO, the background still gets drawn
+  // when editing. This is a problem because the left edge of the background
+  // overlaps the security decoration's hover rect. Return that the textview
+  // is transparent, and follow up below by disabling any background drawing.
+  // This will cause background drawing to fall through to the cell. See
+  // https://crbug.com/669870 .
+  return NO;
+}
+
+- (void)drawViewBackgroundInRect:(NSRect)aRect {
+  // See the comment in -isOpaque.
+}
+
 - (void)drawRect:(NSRect)rect {
   AutocompleteTextFieldObserver* observer = [self observer];
   if (observer)
     observer->OnBeforeDrawRect();
   [super drawRect:rect];
   if (observer)
     observer->OnDidDrawRect();
 }
 
 // ThemedWindowDrawing implementation.
 
 - (void)windowDidChangeTheme {
   [self updateColorsToMatchTheme];
 }
 
 - (void)windowDidChangeActive {
 }
 
 @end